Tony Abbey – University of Leicester MOS1 CCD1 Hot Column Tony Abbey – University of Leicester

XMM impacts history XMM was launched on 10 December 1999 into a highly elliptical orbit and each revolution takes 2 days. Rev 107 – 17 July 2000 – MOS2 – patch of hot pixels on 3 CCDs - questionable whether was due to large proton flare prior to Filter Wheel closing Rev 156 – 15 Oct 2000– PN – several hot pixels suddenly appear Rev 325 – 17 Sept 2001 – MOS1 – bright flash seen, many new hot pixels Rev 961 – 9 March 2005 – MOS1 – bright flash seen, bright column developed on central CCD, total loss of CCD6

Impact rev 961– hot column on CCD1 The new hot column (X=324) unfortunately passes very near to the centre of CCD1. Over a period of a few weeks it appeared to be fading to below threshold, but the next slide shows it is quite variable but with perhaps a slow decline.

Impact rev 961– hot column on CCD1

Impact rev 961– hot column on CCD1 Conclusions No real need to set column 324 as bad because an offset table change can suppress it Set offset for column 324 as appropriate – 123 ADU ? This was done on rev 1044 ? Review level of column 324 at 3 month intervals and adjust as necessary